Scenario: Based on a discussion between a Citrix Architect and team of Workspacelab has been created across three (3) sites.

They captured the following requirements during the design discussion held for NetScaler design projects:

All three (3) Workspacelab sites (DC, NDR, and DR) will have similar NetScaler configuration and design.

Both external and internal NetScaler MPX appliances will have Global Server Load balancing (GSLB) configured and deployed in Active/Passive mode.

GSLB should resolve both A and AAA DNS queries.

In the GSLB deployment, the NDR site will act as backup for the DC site. whereas the DR site will act as backup for the NDR site.

When the external NetScaler replies to DNS traffic coming in through Cisco Firepower IPS, the replies should be sent back through the same path.

On the internal NetScaler, both front-end VIP and back-end SNIP will be part of the same subnet.

USIP is configured on the DMZ NetScaler appliances.

The external NetScaler will act default gateway for back-end servers.

All three (3) sites (DC, NDR, and DR) will have two (2) links to the Internet from different service providers configured in Active/Standby mode.

Which design decision must the architect make to meet the design requirements above?